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Biomedical subjects

R D Orr

Publications and source records attributed to R D Orr.

At least 19 recordsLinked to original sources
PubMed2001

Distribution and retention of 137Cs in sediments at the Hanford Site, Washington.

137Cesium and other contaminants have leaked from single-shell storage tanks (SSTs) into coarse-textured, relatively unweathered unconsolidated sediments. Contaminated sediments were retrieved from beneath a leaky SST to investigate the distribution of adsorbed 137Cs+ across different sediment size fractions. All fractions contained mica (biotite, muscovite, vermiculatized biotite), quartz, and plagioclase along with smectite and kaolinite in the clay-size fraction. A phosphor-plate autoradiograph method was used to identify particular sediment particles responsible for retaining 137Cs+. The Cs-bearing particles were found to be individual mica flakes or agglomerated smectite, mica, quartz, and plagioclase. Of these, only the micaceous component was capable of sorbing Cs+ strongly. Sorbed 137Cs+ could not be significantly removed from sediments by leaching with dithionite citrate buffer or KOH, but a fraction of the sorbed 137Cs+ (5-22%) was desorbable with solutions containing an excess of Rb+. The small amount of 137Cs+ that might be mobilized by migrating fluids in the future would likely sorb to nearby micaceous clasts in downgradient sediments.

Adsorption↗
PubMed2000

Prone position endoscopic transthoracic release with simultaneous posterior instrumentation for spinal deformity: a description of the technique.

STUDY DESIGN: A prospective series of 15 consecutive adult patients with spinal deformity who underwent endoscopic transthoracic release with simultaneous posterior instrumentation while positioned prone. OBJECTIVES: To describe the technique and clinical results of endoscopic transthoracic release performed with the patient prone (as opposed to lateral) on the concave side for scoliosis or on either side for kyphosis, with simultaneous posterior exposure, instrumentation, and correction of the deformity. SUMMARY OF BACKGROUND DATA: Use of endoscopic surgical techniques is rapidly advancing across all subspecialties. These techniques can be used to expose and operate on the spine in a less invasive fashion, thus avoiding damage to other tissues and facilitating earlier mobilization and rehabilitation. Current endoscopic techniques with the patient in the lateral decubitus position mimic open thoracotomy. A new technique is described with the patient positioned prone, which allows simultaneous posterior exposure. METHODS: Preoperative Cobb angle or thoracic kyphosis angle, maximal correction bending films, and postoperative Cobb angle or kyphosis angle were measured and compared. All perioperative morbidity, intraoperative complications, and surgical variables were prospectively documented and analyzed. RESULTS: There were no intraoperative technical problems with the endoscopic equipment or instruments and no immediate, 6-month, or 2-year postoperative complications related to the endoscopic component of the procedure. In the scoliosis patients, the average correction was 60%. In the kyphosis patients, the average correction was 39%. CONCLUSIONS: Transthoracic endoscopic techniques, compared with thoracotomy, offer a less invasive method of accessing the anterior spinal column, with the benefits of an excellent view of the area of the spine being instrumented, minimal soft tissue disruption, and an improved cosmetic result. With the simultaneous technique, staged or subsequent procedures can be eliminated, and a circumferential structural release as well as control of the mobilized spine can be achieved. This simultaneous technique can be extended for use in correction of a variety of thoracic spinal pathologies.

Adolescent↗
PubMed1999

Ethical challenges in infant heart transplantation: a clinical case presentation.

Although heart transplantation has become recognized as a viable option for the treatment of incorrectable heart disease in infants and children, its application becomes less clear in infants with potentially serious neurologic impairment. The following case study illustrates one transplant team's approach to decision making in the case of an infant born with a chromosomal deletion syndrome.

Abnormalities, Multiple↗
PubMed1999

Cervical spondylotic myelopathy. Approaches to surgical treatment.

Cervical spondylotic myelopathy is the leading cause of spinal cord dysfunction in older patients. This review article looks at the natural history of the condition and examines the role of different surgical treatments for it. Anterior and posterior surgical approaches have a role in the treatment of cervical spondylotic myelopathy dependent on the number of levels involved and the alignment of the spine. Anterior decompression and fusion is useful in patients who have disease at three or fewer levels or in patients with kyphotic alignment. In more extensive disease, a posterior decompression and fusion is usually best. Canal expansive laminoplasty is useful in the treatment of myelopathy without radiculopathy in a patient with lordotic alignment. With the exception of laminoplasty, nonfusion procedures have little role in the treatment of cervical spondylotic myelopathy.

Cervical Vertebrae↗
PubMed1998

Atlantoaxial instability complicating radiation therapy for recurrent nasopharyngeal carcinoma. A case report.

STUDY DESIGN: A case report of a patient in whom atlantoaxial instability developed secondary to repeat radiation therapy for recurrent nasopharyngeal carcinoma. OBJECTIVES: To illustrate a dramatic and previously unreported complication of local radiation to the posterior nasopharynx. SUMMARY OF BACKGROUND DATA: Nasopharyngeal carcinoma is an unusual tumor that usually is managed with local, external-beam radiation. It is not thought to involve the cervical spine directly, although local invasion of the skull base is common. METHODS: A review of the medical records and radiographs of the only patient known to develop this complication of radiation used to manage nasopharyngeal carcinoma. RESULTS: Atlantoaxial instability developed in a patient as a result of repeat radiation for a locally recurrent tumor. The instability was associated with intrusion of the anterior arch of C1 into the posterior nasopharynx and was managed successfully with a posterior stabilization using transarticular screws and supplemental wiring. CONCLUSIONS: Patients who have undergone local irradiation for nasopharyngeal carcinoma may be at risk for developing atlantoaxial instability.

Adult↗
PubMed1998

Medicine, ethics and religion: rational or irrational?

Savulescu maintains that our paper, which encourages clinicians to honour requests for "inappropriate treatment" is prejudicial to his atheistic beliefs, and therefore wrong. In this paper we clarify and expand on our ideas, and respond to his assertion that medicine, ethics and atheism are objective, rational and true, while religion is irrational and false.

Cultural Diversity↗
PubMed1997

Reanimation: overcoming objections and obstacles to organ retrieval from non-heart-beating cadaver donors.

Interest in the retrieval of organs from non-heart-beating cadaver donors has been rekindled by the success of transplantation of solid organs and the insufficient supply of donor organs currently obtained from heart-beating cadaver donors. There are currently two retrieval techniques being evaluated, the in situ cold perfusion approach and the controlled death approach. Both, however, raise ethical concerns. Reanimation is a new method which has been used successfully in animals. We believe this new approach overcomes the ethical objections raised to these other methods.

Animals↗
PubMed1997

Requests for "inappropriate" treatment based on religious beliefs.

Requests by patients or their families for treatment which the patient's physician considers to be "inappropriate" are becoming more frequent than refusals of treatment which the physician considers appropriate. Such requests are often based on the patient's religious beliefs about the attributes of God (sovereignty, omnipotence), the attributes of persons (sanctity of life), or the individual's personal relationship with God (communication, commands, etc). We present four such cases and discuss some of the basic religious tenets of the three Abrahamic faith traditions as they relate to such requests. We suggest that religious reasons for requesting "inappropriate" treatment are "special" and deserve serious consideration. We offer guidance to assist clinicians and clinical ethicists as they attempt to resolve these conflicts, emphasising the importance of understanding the religious beliefs of the patient/surrogate and suggesting the assistance of a religious interpreter. We suggest open discussion with patients and families of both the clinical situation and the theological basis for these requests. We also suggest that clinicians use additional religious doctrines or principles from patients' own traditions to balance the reasons behind the requests. We conclude that most persistent requests for "inappropriate" treatment should be honoured.

Adult↗
PubMed1997

Stress and distress in pediatric nurses: lessons from Baby K.

BACKGROUND: Nurses experience stress and suffering when they care for critically ill and dying patients. Moral distress occurs when nurses are unable to translate their moral choices into moral action. In response to this stress, nurses may experience burnout. OBJECTIVE: To investigate the attitudes and perceptions of the nurses who were ordered by the court to provide long-term care for Baby K, a female child with anencephaly. METHOD: A questionnaire was developed to provide descriptive insight into the stress and distress the nurses experienced while caring for Baby K. RESULTS: Nurses caring for Baby K experienced stress and suffering. Although they felt supported and respected as nurses in their workplace, they felt conflict with the legal system. To compensate for feelings of powerlessness, the nurses simply put on a professional face and continued to provide care. They feared making mistakes, many felt guilty and angry, and all felt that they were not included in decision making. CONCLUSIONS: (1) Suffering among caregivers occurs and must be recognized, (2) measures must be taken to reduce the stress and distress of healthcare professionals as they provide care to patients who cannot recover, and (3) in addition to these measures, society must provide guidance to healthcare professionals, especially concerning the care of patients who are permanently unconscious.

Anencephaly↗